Process for protecting a substrate with an arylsulfonamidopyridine intumescent agent

ABSTRACT

INTUMESCENT COMPOSITIONS OF THE INVENTION COMPRISE CERTAIN ARYLSULFONAMIDOPYRIDINES, SUCH AS THE 2-, 3-, AND 4SULFANILAMIDOPYRIDINES. THE INTUMESCENT AGENTS MAY BE EMPLOYED IN CONJUNCTION WITH ADDITIVES CONVENTIONALLY USED IN INTUMESCENT COMPOSITIONS. FOR USE IN PROTECTING SUBSTRATES FROM HEAT AND FIRE, THE INTUMESCENT COMPOSITIONS MAY BE APPLIED TO A SUBSTRATE IN ANY SUITABLE MANNER, SUCH AS BY ELECTRODEPOSITION, SPRAYING ONTO AN ADHESIVE SUBSTRATE, OR THE APPLICATION OF A COATING COMPOSITION COMPRISING THE INTUMESCENT AGENT.

nited States 3,778,303 PROCESS FOR PROTECTING A SUBSTRATE WITH ANARYLSULFONAMIDORYRIDINE INTUMES- CENT AGENT Shirley H. Roth, HighlandPark, N.J., asssignor to Cities Service Company, New York, N.Y. NoDrawing. Filed Feb. 11, 1972, Ser. No. 225,639 Int. Cl. C09d /18; C09k3/28 US. Cl. 117136 6 Claims ABSTRACT OF THE DISCLOSURE Intumescentcompositions of the invention comprise certain arylsulfonamidopyridines,such as the 2-, 3-, and 4- sulfanilamidopyridines. The intumescentagents may be employed in conjunction with additives conventionally usedin intumescent compositions. For use in protecting substrates from heatand fire, the intumescent compositions may be applied to a substrate inany suitable manner, such as by electrodeposition, spraying onto anadhesive substrate, or the application of a coating compositioncomprising the intumescent agent.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to intumescent compositions and more particularly relates tosuch compositions containing a one-component intumescent agent.

Description of the prior art It is known that a substrate may beprotected from heat and fire by the application of an intumescentcomposition. Intumescent compositions of the prior art usually containan intumescent agent having at least three components, i.e., acarbonific, a spumific, and a catalyst; and they are typicallycharacterized by the disadvantages of high cost, low spreading rate,relatively poor efiiciency, poor water resistance, and poorweatherability.

As disclosed in US. Pat. 3,535,130, it has already been discovered thata one-component intumescent agent had advantages over multicomponentintumescent agents. However, the intumescent agents of the patent havepoor adherence to substrates and have an undesirable degree of moisturesensitivity.

SUMMARY OF THE INVENTION wherein Ar is a divalent aromatic residue, R ishydrogen, hydrocarbon, halohydrocarbon, or acyl, and R" is a pyridyl orsubstituted pyridyl radical.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The intumescent agents of theinvention may be any compounds corresponding to the above formula.However, they are preferably compounds wherein Ar is a divalent aromaticresidue derived from benzene or naphthalene or an alkyl, haloalkyl,alkoxy, haloalkoxy, halo,

hydroxy, carboxy, amino, amido, or nitro derivative there-' of. When thearomatic ring bears organic substituents, it

3,778,303 Patented Dec. 11, 1973 is'usually preferred that thesesubstituents contain 1-5 carbon atoms. When there are halo substituents,it is usually preferred that they be chloro or bromo. It is alsopreferred that the aromatic ring have at least one free reactiveposition. 1

As indicated above, R of the formula may be hydrogen or a hydrocarbon,halohydrocarbon, or acyl radical, e.g., an alkyl, chloroalkyl, orbromoalkyl radical containing 1-5 carbon atoms, a phenyl, chlorophenyl,or bromophenyl radical or an aliphatic or aromatic acyl radical. R" ispreferably a pyridyl radical, but it may bear one or more substiuents ifdesired. The substituted pyridyl radicals most commonly found in thesecompounds are the chloro, bromo, iodo, carboxy, hydroxy, amino, amido,nitro, sulfanamido, sulfonate, C -C alkyl, C -C alkoxy, and benzoderivatives, but compounds containing other substituted pyridyl radicalsare also utilizable. When R" is a substituted pyridyl radical, thenitrogen of the sulfonamide group may be attached directly to thepyridine ring, or it may be attached to the pyridine ring through thesubstituent.

Exemplary of the intumescent agents of the invention areZ-sulfanilamidopyridine,

3-sulfanilamidopyridine,

tsulfanilamidopyridine,

2- (4-amino-3 -chlorobenzenesulfonamido pyridine,

2- 2-amino-4-bromobenzenesulfonamido pyridine,

2- 4-amino-2-ethylbenzenesulfonamido )pyridine,

2- S-amino-4-chloromethylbenzenesulfonamido) pyridine,

2- (4-amino-2-butoxyb enzenesulfonamido) pyridine,

2- 4-amino-3-chloromethoxybenzenesulfonamido) pyridine,

2- (4-amino-3-carb oxybenzenesulfonamido) pyridine,

2- 3 ,4-diaminobenzene'sulfonamido) pyridine,

2- (4-amino-2-acetamidobenzenesulfonamido )pyridine,

2- (2-amino-4-nitrobenzenesulfonamido) pyridine,

2- (4-methylaminobenzenesulfonamido) pyridine,

2-(4-chloroethylaminobenzenesulfonamido)pyridine,

2- (4-bromoethylaminobenzenesulfonamido pyridine,

2- (4-phenylaminob enzenesulfonamido) pyridine,

2- [4- (p-chlorophenylamino )benzenesulfonamido] pyridine,

2- [4- (p-bromophenylamino benzenesulfonamido] pyridine,

2- (p-acetamidob enzenesulfonamido) pyridine,

2- p-benzamidobenzene sulfonamido )pyridine,

N -methyl-N -(2-pyridyl) sulfanilamide,

N -propyl-N (2-pyridyl) sulfanilamide,

N -carboxymethyl-N 2-pyridyl sulfanilamide,

N -amidomethyl-N -(2-pyridy1)sulfanilamide,

6-chloro-3-sulfanilamidopyridine,

S-bromo-2-sulfanilamidopyridine,

3-iodo-2-sulfanilamidopyridine,

4-carb oxy-2-sulfanilamidopyridine,

6 hydroxy-2-sulfanilamidopyridine,

2-sulfanilamidoaminopyridine,

6-amino-3 -sulfanilamidopyridine,

2-amido-3-sulfanilamidopyridine,

S-nitro-2-sulfanilamidopyridine,

5-sulfonamido-2-sulfanilamidopyridine,

5- sulfonato-2-sulfanilamidopyridine,

3-methyl-2-sulfanilamidopyridine,

3-ethoxy-2-sulfanilamidopyridine,

5 -dimethylsulfonamido-2-sulfanilamidopyridine,

3-phenylazo-2-sulfanilamidopyridine,

2-sulfanilamidoquinoline,

5-nitro-2-sulfanilamido quinoline,

Z-methyl-6-sulfanilamidoquinoline,

2-hydroxy-4-methyl-7-sulfanilamidoquinoline,

1-sulfanilamidoisoquinoline,

the corresponding naphthalene compounds, etc. When not readilyavailable, these compounds may be prepared by known techniques.

For use in protecting a substrate from heat and fire, the intumescentagents of the invention may be applied in any suitable manner, e.g.,electrodeposition, spraying of powdered intumescent agent onto anadhesive substrate, etc. However, it is usually preferred to compoundthe intumescent agent with a binder, e.g., nitrocellulose, andoptionally also with one or more of the other ingredients conventionallyused in intumescent compositions, e.g., stabilizers, dispersing agents,pigments, driers, biocidcs, anti-foamers, thickeners, protectivecolloids, fillers, blowing agents, etc.; disperse the composition in asuitable liquid medium, e.g., water or a solvent or solvent mixture; andapply the coating composition thus formed to the substrate to beprotected. As is the case with conventional intumescent coatingcompositions, it is frequently convenient to apply these coatingcompositions in the form of a paint having a solids content of about 70%by weight and an intumescent agent/binder weight ratio of about0.075-14/1 to deposit a coating having a dry thickness of about0.00l0.75 inch.

The intumescent agents of the invention are eflicient, have low moisturesensitivity, and intumesce to form foams having good volume, cellstructure, and adherence to substrates, such as wood, metal, andplastics. They are also useful as flame retardants in normally flammablecompositions.

The following examples are given to illustrate the in- 'vention and arenot intended as a limitation thereof.

EXAMPLE I Place one gram of 2-sulfanilamidopyridine in an aluminum panand flame it with a propane torch. The compound intumesces to form anexcellent volume of foam having a good cell structure.

EXAMPLE II It is obvious that many variations may 'be made in theproducts and processes set forth above without departing from the spiritand scope of this invention.

What is claimed is:

1. A process for protecting a substrate from heat and fire whichcomprises applying thereto an intumescent composition comprising as theintumescent agent a compound corresponding to the formula:

wherein Ar is a divalent aromatic residue, R is hydrogen, hydrocarbon,halohydrocarbon, or acyl, and R" is a pyridyl or substituted pyridylradical.

2. The process of claim 1 wherein Ar is a divalent aromatic residuederived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy,haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivativethereof.

3. The process of claim 1 wherein R" is a pyridyl radical or a halo,carboxy, hydroxy, amino, amido, nitro, sulfonamido, sulfonate, alkyl,alkoxy, or benzo derivative thereof.

4. The process of claim 1 wherein the intumescent agent is2-sulfanilamidopyridine.

5. The process of claim 1 wherein the intumescent agent is3-sulfanilamidopyridine.

6. The process of claim 1 wherein the intumescent agent is4-sulfanilamidopyridine.

References Cited UNITED STATES PATENTS 3,535,130 10/1970 Webb 117-136 X3,663,464 5/1972 Sawko 117l36 X 3,707,554 12/1972 Hardy l17136 X OTHERREFERENCES Northey: Sulfanamides, pp. 29 and 68-71 (1948).

WILLIAM D. MARTIN, Primary Examiner H. J. GWINNELL, Assistant ExaminerU.'S. C1. X.R. 106-15 FP

